Effect of oil shale additions on the raw mix and clinker for high belite cement

Raw mixes for high belite cement clinker (HBCC) have been designed on basis of chemical analyses of Egyptian raw materials with and without the additions of Egyptian oil shale obtained from Younis Gharb mine located at the Red Sea Coast in the Eastern desert of Egypt. LSF of the mix was maintained at 80%, silica modulus at 2.25 and C3A in the clinker not exceeding 4%. From raw mix design it was found that, with increase of % shale additions the limestone % in the raw mix decreases whereas % secondary compounds, SO3 and P2O5, increase in the clinker. Two raw mixes, One with about 11 wt% oil shale and one without shale as blank were selected for preparation of HBCC in the laboratory. The investigated firing temperatures were 1300 and 1350°C. Characteristics of the produced high belite clinker, such as chemical composition, X-ray diffraction analysis, scanning electron microscopy besides physico-mechanical properties of its hydrated pastes have been determined and compared with the corresponding values of commercial ordinary Portland cement. It was found that, the most appropriate temperature for firing HBCC raw mixes is 1350oC. Generally, shale additions had slight effect on the physico-mechanical properties of the produced high belite clinker.